This research centers about a migrant population and aims to interpret the development of hypertension and its associated precursors as a function of genetic, environmental and psycho-social factors and their interaction. The Tokelauans, a Polynesian population, have migrated from their traditional atolls, where the prevalence of hypertension is low, to New Zealand, where, by analogy with the experience of other Polynesian groups, hypertension will become a major health problem (along with obesity, diabetes and gout). The extensive data collected on this population includes pre-migrational and post-migrational attributes (physiological, medical, dietary and sociological) and a complete genealogy which allows calculation of all genetic relationships in the population. We intend to collect anthropometric and genetic marker data and to complete a longitudinal study of the population in the two contrasting environments. By investigating these parameters in a series of regression models we aim to answer the following questions that relate to the development of hypertension in the 'high risk' environment and to the distribution of precursors of hypertension in juveniles: 1) Is obesity important and does it have a significant genetic component?; 2) Are changes in morphological growth implicated?; 3) Are changing levels of cholesterol, triglycerides, serum glucose and uric acid affect associated with the development of hypertension?; 4) What is the magnitude of the genetic component?; 5) What is the magnitude of the genotype-environment interaction?; 6) Can the individuals 'at risk' for developing hypertension be identified on the basis of familial attributes, anthropometric characteristics and distribution of genetic markers, before clinical symptoms are expressed? The project thus will attempt a complete analysis of the causual parameters of hypertension in this migrant population and to develop pre-clinical surveillance system. We anticipate that this will serve as a model for the early detection of hypertension and surveillance in more complex situations such as the United States.